Scrappy
Lets the Pokémon's Normal and Fighting moves hit Ghost Pokémon.
Full effect
This Pokémon ignores Ghost-type Pokémon's immunity to Normal- and Fighting-type moves. Ghost Pokémon's other types affect damage as usual.
In game description
The Pokémon can hit Ghost-type Pokémon with Normal- and Fighting-type moves. It is also unaffected by Intimidate.
Pokemon with Scrappy
Using Scrappy in Cobblemon
Abilities are passive and always active, so Scrappy costs you nothing to run. If it is marked hidden on a species above, expect it to be harder to obtain: servers differ in whether hidden abilities come from breeding, an Ability Patch, or events.
See the Pokedex for which abilities each species can have, and IVs, EVs and breeding for how to actually pass one down.